Radio communications systems and methods can be used to transmit and receive data. Bluetooth, for example, is an open specification for a radio system that provides a network infrastructure to enable short range wireless communication of data and voice. It comprises a hardware component and a software component. The specification also describes usage models and user profiles for these models.
Bluetooth radios may operate in the unlicensed ISM band at 2.4 Gigahertz using 79 channels between 2.400 GHz to 2.4835 GHz (23 channels in some countries). The range for Bluetooth communication may be on the order of 0–30 feet (10 meters) with a power consumption of 0 dBm (1 mW). This distance can be increased to 100 meters by amplifying the power to 20 dBm. The Bluetooth radio system may be optimized for mobility.
The baseband and the Link control layers enable the physical RF link between Bluetooth devices to form a piconet. Both circuit and packet switching can be used. Two kinds of physical links can be provided using the baseband packets: Synchronous connection oriented links (SCO) and Asynchronous connectionless links (ACL). The ACL link may provide a packet switched link typically suitable to carry data traffic, while the SCO link may provide a circuit switched link typically suitable to carry audio traffic.
The link manager protocol is responsible for the link setup between Bluetooth units. This protocol layer caters to issues of security such as authentication, encryption by generating, exchanging and checking the link and encryption keys. It also deals with control and negotiation of link parameters such as baseband packet sizes.
The Bluetooth logical link control and adaptation layer supports higher level multiplexing, segmentation and reassembly of packets, and Quality of Service (QoS) communication and Groups. This layer may use the baseband ARQ to ensure reliability. Channel identifiers may be used to label each connection end point.
Bluetooth protocols are discussed, for example, in the reference by Sailesh Rathi entitled “BlueTooth Protocol Architecture” (Dedicated System Magazine, 2000 Q4, pages 28–33). Bluetooth protocols are also discussed in the reference by Brent A. Miller et al. entitled “BLUETOOTH REVEALED: The Insider's Guide To An Open Specification For Global Wireless Communications” (Prentice Hall PTR, Upper Saddle River, N.J., 2001). Both of these references are hereby incorporated herein in their entirety by reference.